LinkedAccounts dialog: add frame around list

The border added is similar to the one in Change Addressbook dialog

Fix: https://bugzilla.gnome.org/show_bug.cgi?id=709099
window: Set the icon name of the window as "x-office-address-book"

For the fallback app-menu in the headerbar.

https://bugzilla.gnome.org/show_bug.cgi?id=722014
gitignore: updated, add appdata file
window: Fix the location of the buttons in the headerbar when is split

https://bugzilla.gnome.org/show_bug.cgi?id=722013
build: remove margin_left/right deprecated calls

Remove some additional code added to deal with locales RTL